Giant Rockets Could Revolutionize Astronomy

Jan.
14, 2009: In the game of astronomy, size matters.
To get crisp, clear images of things billions of light years
away, a telescope needs to be big.

"The
bigger the better," says astronomer Harley Thronson,
who leads advanced concept studies in astronomy at the Goddard
Space Flight Center. And he thinks "NASA's new Ares V
rocket is going to completely change the rules of the game."

Ares
V is the rocket that will deliver NASA's next manned lunar
lander to the moon as well as all the cargo needed for a lunar
base. Its roomy shroud could hold about eight school buses,
and the rocket will pack enough power to boost almost 180,000
kg (396,000 lbs -- about 16 or 17 school buses) into low Earth
orbit. Ares V can haul six times more mass and three times
the volume the space shuttle can.

"Imagine
the kind of telescope a rocket like that could launch,"
says Thronson. "It could revolutionize astronomy."

Right:
The roomy shroud of the Ares V could hold about eight school
buses. Credit: NASA

Optical
engineer Phil Stahl of the Marshall Space Flight Center offers
this example: "Ares V could carry an 8-meter diameter
monolithic telescope, something that we already have the technology
to build. The risk would be relatively low, and there are
some big cost advantages in not having to cram a large telescope
into a smaller launcher."

For
comparison, he points out that Hubble is only 2.4 meters wide.

An
8-meter monolithic telescope would see things more than three
times as sharply as Hubble can. More importantly, in the same
amount of observing time, the larger mirror would see objects
that are about 11 times fainter than Hubble sees because the
8-meter telescope has 11 times the light collecting area.

But
Ares V can go yet bigger. It could transport a huge segmented
telescope â one with several separate mirror panels that are
folded up for transport like the James Webb Space Telescope--but
three times the size!

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The
Space Telescope Science Institute's Marc Postman has been
planning a 16-meter segmented optical/ultraviolet telescope
called ATLAST, short for Advanced Technology Large-Aperture
Space Telescope. The science from an aperture its size would
be spectacular.

"ATLAST
would be nearly 2000 times more sensitive than the Hubble
Telescope and would provide images about seven times sharper
than either Hubble or James Webb," says Postman. "It
could help us find the long sought answer to a very compelling
question -- 'Is there life elsewhere in the galaxy?'"

ATLAST's
superior sensitivity would allow astronomers to hugely increase
their sample size of stars for observation. Then, discovery
of planets hospitable to life could be just around the corner!

"With
our space-based telescope, we could obtain the spectrum of
Earth-mass planets orbiting a huge number of nearby [60 -
70 light years from Earth] stars," says Postman. "We
could detect any oxygen and water in the planets' spectral
signatures. ATLAST could also precisely determine the birth
dates of stars in nearby galaxies, giving us an accurate description
of how galaxies assemble their stars."

This
telescope could also probe the link between galaxies and black
holes. Scientists know that almost all modern galaxies have
supermassive black holes in their centers. "There must
be a fundamental relationship between the formation of supermassive
black holes and the formation of galaxies," explains
Postman, "but we don't understand the nature of that
relationship. Do black holes form first and act as seeds for
the growth of galaxies around them? Or do galaxies form first
and serve as incubators for supermassive black holes? A large
UV/optical telescope could answer this question: If our telescope
finds ancient galaxies that do not have supermassive black
holes in their centers, it will mean galaxies can exist without
them."

Dan
Lester of the University of Texas at Austin envisions another
16-meter telescope, this one for detecting far-infrared wavelengths.

"The
far-infrared telescope is quite different from, and quite
complementary to, the optical telescopes of Stahl and Postman,"
says Lester. "In the far-infrared part of the spectrum,
we generally aren't looking at starlight itself, but at the
glow of warm dust and gas that surrounds the stars. In the
very early stages of star formation, the proto-star is surrounded
by layers of dust that visible light can't penetrate. Our
telescope will allow us to see down into the innards of these
giant dense clouds that are forming stars deep inside."

Observations in the far-infrared are especially challenging.
These long wavelengths are hundreds of times larger than visible
light, so it's hard to get a clear picture. "A
very big telescope is necessary for good clarity at IR wavelengths,"
notes Lester.

Above:
An artist's concept of the Single Aperture Far-Infrared Telescope
(SAFIR) that could be launched aboard the Ares V. [

Like
the telescopes of Stahl and Postman, Lester's Single Aperture
Far-Infrared Telescope ('SAFIR' for short), comes in two flavors
for the Ares V: an 8-meter monolithic version and a 16-meter
segmented version. Lester realized that, with an Ares V, he
could launch an 8-meter telescope that didn't need complicated
folding and unfolding. "But on the other hand, if we
don't mind adding the complexity and cost of folding and still
use an Ares V, we could launch a really mammoth telescope,"
says Lester.

In
addition to all the above telescopes, Ares V could boost an
8-meter-class X-ray telescope into space. NASA's highly-successful
Chandra X-ray Observatory has a 1 meter diameter mirror, so
just imagine what an 8-meter Chandra might reveal!

Roger
Brissenden of the Chandra X-ray Center is excited about the
possibility of a future 8-meter-class X-ray telescope called
Gen-X.

"Gen-X
would be an extraordinarily powerful X-ray observatory that
could open up new frontiers in astrophysics," he says.
"This telescope will observe the very first black holes,
stars and galaxies, born just a few hundred million years
after the Big Bang, and help us determine how these evolve
with time. Right now, the study of the young universe is almost
purely in the realm of theory, but with Gen-X's extreme sensitivity
(more than 1000 times that of Chandra) these early objects
would be revealed."

Indeed,
Ares V flings shutters open wide on our view of the cosmos.
It shakes off the shackles of mass and volume constraints
from science missions and sweeps us into deep space to view
"...a hundred things/ You have not dreamed of."

"We
could get incredible astronomy from this big rocket,"
says Thronson, a professional dreamer. "I can't wait."

Scientists
at the recent International
Astronautical Congress in Scotland spent an entire
workshop session brainstorming about "out of this
world" missions large launch vehicles could make
possible, and the Ares V could fly every one of the
missions suggested.